DESCRIPTION (provided by principal investigator): Adults aged 75 years and older are at high risk for acute events (i.e. hospitalizations, falls, and driving cessation), associated with declines in mobility and social participation, functional domains integral to quality of life. Appropriate social support, lower symptom burden, and post- event service and resource use can contribute to maintenance of mobility and participation despite age-related impairments, disease, and declines in task-specific abilities. Nearly all previous epidemiological research on age-related functional change has focused on specific mobility-related activities. UAB Study of Aging investigators have advanced knowledge about age-related changes in social participation using the Life-space Assessment (LSA), an interview tool they developed to evaluate mobility among community-dwelling older adults. The LSA reflects distance, frequency, and independence of movement in five geographically defined zones, extending from the room where one sleeps to beyond town, in the four weeks before the assessment. Available data suggest that socio-demographic factors, physical, emotional, and cognitive health all predict changes in life-space over 6 months and longer periods. The underlying hypothesis of this application is that many declines in social participation after age 75 are due to residual effects of more immediate (within one month) responses to specific acute events, rather than a gradual equivalent decline. We propose a new prospective observational study of 500 community-dwelling adults aged 75 years and older (the UAB Study of Aging II) to address the following aims: 1) Assess the immediate magnitude of LSA changes associated with specific events commonly occurring among community-dwelling adults aged 75 years and older and follow changes in life-space after the occurrence of the events; 2) Determine if life- space changes over one-month predict subsequent adverse outcomes, i.e. ADL/IADL difficulty, nursing home placement and death; and 3) Examine the role of social support, symptom burden and post-event services and resources on changes in LSA. This study will include a baseline in- home assessment in 2010-2011 to document known predictors of life-space. Monthly follow-up telephone interviews will assess life-space, ADL/IADL, and vital status over a three-year period. Multilevel change or random-effects regression models will be used to examine life-space trajectories over time and Cox proportional hazards models to evaluate predictors of adverse outcomes. Findings will be used to identify the magnitude of life-space changes associated with specific events, to identify factors that moderate precipitous life-space mobility changes, and to guide the development and testing of interventions to optimize life-space mobility in late life. PUBLIC HEALTH RELEVANCE: The late life period after age 75 is a time when adults are more likely to experience illness and hospitalizations, the development of new conditions, personal losses, memory problems, and be at risk for nutritional deficits. As a result, this period of life is associated with an increased risk for mobility loss and decreased social participation. This study will differentiate the causes of gradual and acute causes of changes in mobility and participation in society among community-dwelling older adults. By identifying potentially modifiable causes for decline in mobility after age 75, we will be able to develop interventions designed to enhance participation and quality of life for the burgeoning number of adults entering late life.